The present invention relates to DWDM networks. More specifically, the invention relates to techniques for providing Add/Drop Multiplexers (ADMs) utilizing a pair of muxponders.
There is a growing demand for services and bandwidth in networking. Since the 1980s, Synchronous Optical Network/Synchronous Digital Hierarchy (SONET/SDH) has provided protection, management and support for a transparent mix of traffic protocols over optical networks.
The subsequent deployment of Dense Wavelength Division Multiplex (DWDM) networks increased the existing fiber bandwidth, but the protection and management capabilities of SONET/SDH were lacking.
The Optical Transport Network (OTN) was developed to combine the protection and management capabilities of SONET/SDH with the bandwidth expandability of DWDM. ITU-T G.709 Network Node Interface for the Optical Transport Network, March 2003, define frames that include operation, administration, and maintenance capabilities as well as Forward Error Correction (FEC), which can be utilized to reduce transmission errors.
In a metro WDM/SONET network, there is a need to transport four OC-48 (Optical Channel) signals multiplexed into and OTN ring, with the OTU-2 (Optical Transport Unit) signal being converted into the wavelength of a WDM system. Currently, many components are utilized to perform this functionality.
For example, one could use one to four OC-48 linecards, a crossconnect, one or two OC-192 linecards, and a related transponder for G.709/WDM mapping. Although this solution may be satisfactory, the cost for the many components may be more than is necessary.
Accordingly, what is needed is an innovative way to provide transparent add/drop multiplexing of OC-48/STM-16 signals into an OTN/DWDM ring without unnecessary cost. Additionally, it would be beneficial to provide trunk and client side protection as well as add/drop capability in intermediate node.